修复验收：修正最终验收证据问题

scripts/qa/login_probe.py

@@ -28,7 +28,9 @@ def get_captcha_code_from_redis(uuid):
 def main():
     env = load_qa_env()
     username = env.get('QA_ADMIN_USERNAME', 'admin')
-    password = env.get('QA_ADMIN_PASSWORD', 'admin123')
+    password = env.get('QA_ADMIN_PASSWORD')
+    if not password:
+        raise RuntimeError("QA_ADMIN_PASSWORD is required and must be configured in environment or ~/.railwaysystem-qa.env")
     base_url = 'http://127.0.0.1:1024'
 
     with sync_playwright() as p: